Mon·Apr 11, 2022Monday·April 11, 2022

1. 01*

   Dynamically Induced Topological Inflation

   Gongjun Choi🇨🇭 · Weikang Lin🇨🇳 · Tsutomu T. Yanagida🇨🇳

   We propose an inflation model in which the inflationary era is driven by the strong dynamics of $Sp(2)$ gauge theory. The quark condensation in the confined phase of $Sp(2)$ gauge theory generates the inflaton potential comparable to the energy of the thermal bath at the time of phase transition. Afterwards, with super-Planckian global minimum, the inflation commences at a false vacuum region lying between true vacuum regions and hence the name "topological inflation". Featured by the huge separation between the scale of the false vacuum ($V(0{)}^{1/4}\sim 10^{15}\mathrm{GeV}$) and the global minimum ($⟨\varphi ⟩\sim M_P$), the model can be consistent with CMB observables without suffering from the initial condition problem. Crucially, this is achieved without any fine-tuning of parameters in $V(\varphi )$. In addition to $Sp(2)$, this model is based on an anomaly free $Z_{6R}$ discrete $R$ symmetry. Remarkably, while all parameters are fixed by CMB observations, the model predicts a hierarchy of energy scales including the inflation scale, SUSY-breaking scale, R-symmetry breaking scale, Higgsino mass and the right-handed neutrino mass given in terms of the dynamical scale of $Sp(2)$.

   hep-phastro-ph.COgr-qchep-thPRD(2023)·2 citations
2. 02*

   Standard model anomalies: Lepton flavour non-universality, g-2 and W-mass

   Alessandra D'Alise🇮🇹 · Guglielmo De Nardo🇮🇹 · Maria Grazia Di Luca🇮🇹 · Giuseppe Fabiano🇮🇹 · Domenico Frattulillo🇮🇹 · Giovanni Gaudino🇮🇹 · Davide Iacobacci🇮🇹 · Mario Merola🇮🇹 · Francesco Sannino🇩🇰 · Pietro Santorelli🇮🇹 · Natascia Vignaroli🇮🇹

   We critically analyze the body of results that hints to the existence of New Physics from possible violations of lepton universality observed by the LHCb experiment in the $\mu /e$ ratios $R_K$ and $R_{K^{\ast }}$ to the $g-2$ lepton anomalies. The analysis begins with a theoretical, in depth, study of the $\mu /e$ ratios $R_K$ and $R_{K^{\ast }}$ as well as the process $B_s\to {\mu }^{+}{\mu }^{-}$. Here we consider the impact of complex Wilson coefficients and derive constraints on their imaginary and real parts. We then move to a comprehensive comparison with experimental results. We show that, by fitting a single Wilson coefficient, the deviations from the Standard Model are at the $4.7\sigma$ level when including only the hadronic insensitive observables while it increases to $6.1\sigma$ when including also the hadronic sensitive ones. When switching on all relevant Wilson coefficients and combining both hadronic sensitive and insensitive data into the fit, the deviation from the Standard Model peaks at $7.2\sigma$ and decreases at the $4.9\sigma$ level if we assume that the central values of $R_K$ and $R_{K^{\ast }}$ are taken to be unity. We further estimate other unaccounted for SM contributions and show that their inclusion still requires New Physics to fit the data. We then introduce the $g-2$ lepton anomalies as well as the most recent $W$-mass results. Different theoretical models are considered that can explain the discrepancies from the Standard Model. In the final part of our work we estimate the impact of the forthcoming data from LHCb (coming from LHC Run3) and Belle II, when it will have accumulated about $5a{b}^{-1}$.

   hep-phhep-lathep-thJHEP(2022)·23 citations
3. 03*

   Inert Higgs Dark Matter for CDF-II W-boson Mass and Detection Prospects

   Yi-Zhong Fan🇨🇳 · Tian-Peng Tang🇨🇳 · Yue-Lin Sming Tsai🇨🇳 · Lei Wu🇨🇳

   The $W$-boson mass, which was recently measured at FermiLab with an unprecedented precision, suggests the presence of new multiplets beyond the Standard Model (SM). One of the minimal extensions of the SM is to introduce an additional scalar doublet, in which the non-SM scalars can enhance $W$-boson mass via the loop corrections. On the other hand, with a proper discrete symmetry, the lightest new scalar in the doublet can be stable and play the role of dark matter particle. We show that the inert two Higgs doublet model can naturally handle the new $W$-boson mass without violating other constraints, and the preferred dark matter mass is between $54$ and $74$ GeV. We identify three feasible parameter regions for the thermal relic density: the $SA$ co-annihilation, the Higgs resonance, and the $SS\to W{W}^{\ast }$ annihilation. We find that the first region can be fully tested by the HL-LHC, the second region will be tightly constrained by direct detection experiments, and the third region could yield detectable GeV gamma-ray and antiproton signals in the Galaxy that may have been observed by Fermi-LAT and AMS-02.

   hep-phastro-ph.COastro-ph.HEPRL(2022)·134 citations
4. 04*

   Electroweak Precision Fit and New Physics in light of $W$ Boson Mass

   Chih-Ting Lu🇨🇳 · Lei Wu🇨🇳 · Yongcheng Wu🇨🇳 · Bin Zhu🇨🇳

   The $W$ boson mass is one of the most important electroweak precision observables for testing the Standard Model or its extensions. The very recent measured $W$ boson mass at CDF shows about $7\sigma$ deviations from the SM prediction, which may challenge the internal consistency of the SM. By performing the global electroweak fit with the new $W$-boson, we present the new values of the oblique parameters: $S=0.06\pm 0.10$, $T=0.11\pm 0.12$, $U=0.13\pm 0.09$, or $S=0.14\pm 0.08$, $T=0.26\pm 0.06$ with $U=0$ and the corresponding correlation matrices, which strongly indicates the need for the non-degenerate multiplets beyond the SM. As a proof-of-concept, we show that the new results can be accommodated in the two-Higgs doublet model, where the charged Higgs boson has to be either heavier or lighter than both two heavy neutral Higgs bosons. Therefore, searching for these non-SM Higgs bosons will provide a complementary way to test the new physics for the $W$ boson mass anomaly.

   hep-phhep-exPRD(2022)·192 citations
5. 05*

   Exploring the Universality of Hadronic Jet Classification

   Kingman Cheung🇹🇼 · Yi-Lun Chung🇹🇼 · Shih-Chieh Hsu🇺🇸 · Benjamin Nachman🇺🇸

   The modeling of jet substructure significantly differs between Parton Shower Monte Carlo (PSMC) programs. Despite this, we observe that machine learning classifiers trained on different PSMCs learn nearly the same function. This means that when these classifiers are applied to the same PSMC for testing, they result in nearly the same performance. This classifier universality indicates that a machine learning model trained on one simulation and tested on another simulation (or data) will likely be optimal. Our observations are based on detailed studies of shallow and deep neural networks applied to simulated Lorentz boosted Higgs jet tagging at the LHC.

   hep-phcs.LGhep-exEPJC(2022)·4 citations
6. 06*

   Testing the seesaw mechanisms via displaced right-handed neutrinos from a light scalar at the HL-LHC

   Wei Liu🇨🇳 · Jiale Li🇨🇳 · Jing Li🇨🇳 · Hao Sun🇨🇳

   We investigate the pair production of right-handed neutrinos from the decay of a light $B-L$ scalar in the $U(1{)}_{B-L}$ model. The $B-L$ scalar mixes to the SM Higgs, and the physical scalar is required to be lighter than the observed Higgs. The produced right-handed neutrinos are predicted to be long-lived according to the type-I seesaw mechanism, and yield potentially distinct signatures such as displaced vertex and time-delayed leptons at the CMS/ATLAS/LHCb, as well as signatures at the far detectors including the CODEX-b, FACET, FASER, MoEDAL-MAPP and MATHUSLA. We analyze the sensitivity reach at the HL-LHC for the right-handed neutrinos with masses of 2.5 $\sim$ 30 GeV, showing that the active-sterile mixing to muons can be probed to $V_{\mu N}\sim 10^{-5}$ at the CMS/ATLAS/LHCb using the displaced vertex searches, and one magnitude lower at the MATHUSLA/CMS using time-delayed leptons searches, reaching the parameter space interesting for type-I seesaw mechanisms.

   hep-phPRD(2022)·18 citations
7. 07*

   Definition and evolution of transverse momentum dependent distribution of twist-three

   Simone Rodini · Alexey Vladimirov

   We present an in-depth analysis of transverse momentum dependent (TMD) distributions of twist-three. In particular, we focus on evolution equations, symmetry relations, parameterization, interpretation, small-b asymptotic behaviour and the structure of singularities. The starting point of discussion are the correlators with the definite TMD-twist. By considering suitable combinations of these correlators, we introduce physical TMD distribution of twist-three that can be used for practical applications. We also establish relations with generic TMD distribution of twist-three, and demonstrate that their evolution equations are autonomous in the large-$N_c$ limit.

   hep-phhep-th
8. 08*

   The strong coupling $g_{XJ/\psi \varphi }$ of $X(4700)\to J/\psi \varphi$ in the light-cone sum rules

   Yiling Xie🇨🇳 · Dazhuang He🇨🇳 · Xuan Luo🇨🇳 · Hao Sun🇨🇳

   We assign the scalar tetraquark and the D-wave tetraquark state for $X(4700)$ and calculate the width of the decay $X(4700)$ $\to J/\psi \varphi$ within the framework of light-cone sum rules. The strong coupling $g_{XJ/\psi \varphi }$ is obtained by considering the technique of soft-meson approximation. We also investigate the mass and the decay constant of $X(4700)$ in the framework of SVZ sum rules. Our prediction for the mass is in agreement with the experimental measurement, and that for the decay width of $X(4700)$ $\to J/\psi \varphi$ support the possibility that $X(4700)$ could be a scalar tetraquark state if $X(4700)$ $\to J/\psi \varphi$ is the predominant decay channel, or a D-wave tetraquark state if $X(4700)$ $\to J/\psi \varphi$ is not the predominant one and there exist other decays.

   hep-phNPB(2023)·4 citations
9. 09*

   WG3 Summary -- Rare $B$, $D$ and $K$ decays

   Diego Guadagnoli🇫🇷 · Christoph Langenbruch🇩🇪 · Elisa Manoni🇮🇹

   We summarize the presentations made within Working Group 3 of the CKM2021 workshop. This working group is devoted to rare $B$, $D$ and $K$ decays, radiative and electroweak-penguin decays, including constraints on $V_{\mathrm{td}}/V_{\mathrm{ts}}$ and ${ϵ}^{\prime }/ϵ$. The working group has thus a very broad scope, and includes very topical subjects such as the coherent array of discrepancies in semi-leptonic $B$ decays. Each contribution is here summarized very succinctly with the aim of providing an overview of the main results. The reader interested in fuller details is referred to the individual contributions.

   hep-phPoS(2023)·2 citations
10. 10*

    Effects of isospin violation in the $e^{+}{e}^{-}\to B^{(\ast )}{\bar{B}}^{(\ast )}$ cross sections

    A.E. Bondar🇷🇺 · A.I. Milstein🇷🇺 · R.V. Mizuk🇷🇺 · S.G. Salnikov🇷🇺

    Model estimates are obtained for the influence of Coulomb effects on the ratio of the cross sections for the production of charged and neutral $B\bar{B}$ and $B^{\ast }{\bar{B}}^{\ast }$ pairs in $e^{+}{e}^{-}$ annihilation. It is shown that the difference between the masses of charged and neutral mesons obtained under the assumption that this ratio is constant on a scale of the order of the beam energy spread can differ from the true one by $\delta M\sim 0.03\text{mbox}MeV$ at the energy of ${\rm Y}(5S)$ and by $\delta M\sim 0.4\text{mbox}MeV$ at the energy of ${\rm Y}(4S)$. Thus, the errors given in the PDG for the difference between the masses of charged and neutral $B$ mesons, based on the results obtained at the energy of ${\rm Y}(4S)$, are strongly underestimated. Similar measurements at the energy of ${\rm Y}(5S)$ will have an order of magnitude smaller systematic shift for the mass difference. This circumstance should be taken into account when planning future experiments at the $B$ factory in KEK.

    hep-phhep-exJHEP(2022)·7 citations
11. 11*

    Passage of millicharged particles in the electron beam-dump: refining constraints from SLACmQ and estimating sensitivity of NA64e

    Nataliya Arefyeva🇷🇺 · Sergei Gninenko🇷🇺 · Dmitry Gorbunov🇷🇺 · Dmitry Kirpichnikov🇷🇺

    Millicharged particles (MCPs) arise in many well-motivated extensions of the Standard Model and are a popular subject for experimental searches. We investigate attenuation of the MCP flux produced at accelerator experiments due to their interactions in the media. Considering, as an example, the dedicated MCP search at SLACmQ, we demonstrate that this effect can significantly affect the final sensitivity to the MCP parameter space leaving its essential part still unexplored. Applying our analysis to the SLACmQ experiment [53], we correct their exclusion bounds in close accordance with Ref. [54]. We also show that this newly reopened area with the MCP masses in the range $10^{-4}$ eV - $1$ GeV and charges $\gtrsim 10^{-5}e$ can be effectively probed by the NA64$e$ experiment at the CERN SPS. Light MCPs are mostly produced by virtual photon in electron scattering off nucleus. The main source of heavy MCP is decays of vector mesons, produced by the electrons on nuclei.

    hep-phPRD(2022)·19 citations
12. 12*

    Hadronic Uncertainties versus New Physics for the $W$ boson Mass and Muon $g-2$ Anomalies

    Peter Athron🇨🇳 · Andrew Fowlie🇨🇳 · Chih-Ting Lu🇨🇳 · Lei Wu🇨🇳 · Yongcheng Wu🇨🇳 · Bin Zhu🇨🇳

    There are now two single measurements of precision observables that have major anomalies in the Standard Model: the recent CDF measurement of the $W$ mass shows a $7\sigma$ deviation and the Muon $g-2$ experiment at FNAL confirmed a long-standing anomaly, implying a $4.2\sigma$ deviation. Doubts regarding new physics interpretations of these anomalies could stem from uncertainties in the common hadronic contributions. We demonstrate that these two anomalies pull the hadronic contributions in opposite directions by performing electroweak fits in which the hadronic contribution was allowed to float. The fits show that including the $g-2$ measurement worsens the tension with the CDF measurement and conversely that adjustments that alleviate the CDF tension worsen the $g-2$ tension beyond $5\sigma$. This means that if we adopt the CDF $W$ mass measurement, the case for new physics in either the $W$ mass or muon $g-2$ is inescapable regardless of the size of the SM hadronic contributions. Lastly, we demonstrate that a mixed scalar leptoquark extension of the Standard Model could explain both anomalies simultaneously.

    hep-phNature Commun.(2023)·113 citations
13. 13*

    Light and Feebly Interacting Non-Abelian Vector Dark Matter Produced Through Vector Misalignment

    Fatemeh Elahi🇩🇪 · Sara Khatibi🇮🇷

    In this paper, we examine the evolution of light and feebly interacting non-abelian dark gauge bosons dark matter in the early universe. We specifically work on a multi-component dark matter scenario with a $SU(2{)}_{{}_R}$ gauge symmetry, spontaneously broken by a scalar $\varphi$. For sufficiently light $\lesssim O(\mathrm{MeV})$ and feebly interacting $(g_{{}_R}\lesssim 10^{-10})$ gauge bosons, $W_{{}_R}^3$ and $W_{{}_R}^{\pm }\equiv W_{{}_R}^1\pm i{W}_{{}_R}^2$ become the dark matter candidates. In this study, the portal between the dark sector and the standard model sector is provided by the right-handed electron charged under $SU(2{)}_{{}_R}$. We show that in the region of the parameter space where $g_{{}_R}\sim 10^{-12}$, the dark gauge boson $W_{{}_R}^3$ can be produced efficiently via the freeze-in mechanism, however, this mechanism fails to produce $W_{{}_R}^{\pm }$ sufficiently. For smaller dark gauge coupling, the relic density of three dark matter components can be obtained via the vector misalignment mechanism. Vector misalignment has already been discussed in the case of dark photon dark matter. In this study, we extend the arguments to non-abelian gauge bosons. After discussing the evolution of $W_{{}_R}$s in the early universe, we study the model's constraints and show the parameter space's allowed region.

    hep-phPLB(2023)·5 citations
14. 14*

    Pursuit of new physics within the ${\Lambda }_c\to \Delta K$ decays

    Di Wang🇨🇳

    We point out the $CP$ asymmetry in the chain decay of ${\Lambda }_c^{+}\to {\Delta }^{+}K(t)(\to {\pi }^{+}{\pi }^{-})$ is determined by the branching fractions of ${\Lambda }_c^{+}\to {\Delta }^{++}{K}^{-}$, ${\Lambda }_c^{+}\to {\Delta }^{+}{K}_{S,L}^0$ and ${\Lambda }_c^{+}\to {\Delta }^0{K}^{+}$ modes under the isospin symmetry. The ambiguities from loop-induced quantities and $SU(3{)}_F$ breaking hadronic effects are avoided. Once the $CP$ asymmetry in the ${\Lambda }_c^{+}$ decays into ${\Delta }^{+}$ and neutral kaons is confirmed by experiments, we can check if it is beyond the Standard Model, or verify the $CP$-violating effect resulted from the interference between the Cabibbo-favored and the doubly Cabibbo-suppressed amplitudes with the neutral kaon mixing. Future measurements of branching fractions play a critical role in reducing the uncertainties.

    hep-phhep-exEPJC(2022)·2 citations
15. 15*

    Transport coefficients of heavy quarkonia comparing with heavy quark coefficients

    Juhee Hong🇰🇷 · Su Houng Lee🇰🇷

    We revisit the transport coefficients of heavy quarkonia moving in high-temperature QCD plasmas. The thermal width and mass shift for heavy quarkonia are closely related to the momentum diffusion coefficient and its dispersive counterpart for heavy quarks, respectively. For quarkonium at rest in plasmas the longitudinal gluon part of the color-singlet self-energy diagram is sufficient to determine the leading-order thermal width, whereas the momentum dependence is obtained from the transverse gluon channel. Using the quarkonium-gluon effective vertex based on the dipole interaction of color charges, we discuss the damping rate, the effective rest and kinetic mass shifts of slowly moving quarkonia and compare with the corresponding coefficients of heavy quarks.

    hep-phnucl-thPLB(2022)·1 citation
16. 16*

    Is the $W$-boson mass enhanced by the axion-like particle, dark photon, or chameleon dark energy?

    Guan-Wen Yuan🇨🇳 · Lei Zu🇨🇳 · Lei Feng🇨🇳 · Yi-Fu Cai🇨🇳 · Yi-Zhong Fan🇨🇳

    The $W$-boson mass ($m_W=80.4335\pm 0.0094\mathrm{GeV}$) measured by the Collider Detector at Fermilab collaboration is greater than the standard model (SM) prediction at a confidence level of $7\sigma$, strongly suggesting the presence of new particles or fields. In the literature, various new particles and/or fields have been introduced to explain the astrophysical and experimental data, and their presence, in principle, may also enhance the $W$-boson mass. In this study, we investigate axion-like particle (ALP), dark photon (DP), and chameleon dark energy (DE) models for a solution to the $W$-boson mass excess. We find that the ALP and DP interpretations have been significantly narrowed down by global electroweak fits. The possibility of attributing the $W-$boson mass anomaly to the chameleon DE is ruled out by other experiments.

    hep-phastro-ph.COastro-ph.HEhep-thSCPMA(2022)·68 citations
17. 17*

    Interpreting electroweak precision data including the $W$-mass CDF anomaly

    Alessandro Strumia🇮🇹

    We perform a global fit of electroweak data, finding that the anomaly in the $W$ mass claimed by the CDF collaboration can be reproduced as a universal new-physics correction to the $T$ parameter or $|H^{†}{D}_{\mu }H{|}^2$ operator. Contributions at tree-level from multi-TeV new physics can fit the anomaly compatibly with collider bounds: we explore which scalar vacuum expectation values (such as a triplet with zero hypercharge), $Z^{\prime }$ vectors (such as a $Z^{\prime }$ coupled to the Higgs only), little-Higgs models or higher-dimensional geometries provide good global fits. On the other hand, new physics that contributes at loop-level must be around the weak scale to fit the anomaly. Thereby it generically conflicts with collider bounds, that can be bypassed assuming special kinematics like quasi-degenerate particles that decay into Dark Matter (such as an inert Higgs doublet or appropriate supersymmetric particles).

    hep-phhep-exJHEP(2022)·153 citations
18. 18*

    Looking at QED with Dyson-Schwinger equations: basic equations, Ward-Takahashi identities and the two-photon-two-fermion irreducible vertex

    Orlando Oliveira🇵🇹 · Helena Lessa Macedo🇵🇹 · Rodrigo Carmo Terin🇧🇷

    A minimal truncated set of the integral Dyson-Schwinger equations, in Minkowski spacetime, that allows to explore QED beyond its perturbative solution is derived for general linear covariant gauges. The minimal set includes the equations for the fermion and photon propagators, the photon-fermion vertex, and the two-photon-two-fermion one-particle-irreducible diagram. If the first three equations are exact, to build a closed set of equations, the two-photon-two-fermion equation is truncated ignoring the contribution of Green functions with large number of external legs. It is shown that the truncated equation for the two-photon-two-fermion vertex reproduces the lowest-order perturbative result in the limit of the small coupling constant. Furthermore, this equation allows to define an iterative procedure to compute higher order corrections in the coupling constant. The Ward-Takahashi identity for the two-photon-two-fermion irreducible vertex is derived and solved in the soft photon limit, where one of the photon momenta vanish, in the low photon momenta limit and for general kinematics. The solution of the Ward-Takahashi identity determines the longitudinal component of the two-photon-two-fermion irreducible vertex, while it is proposed to use the Dyson-Schwinger equation to determine the transverse part of this irreducible diagram. The two-photon-two-fermion DSE is solved in heavy fermion limit, considering a simplified version of the QED vertices. The contribution of this irreducible vertex to a low-energy effective photon-fermion vertex is discussed and the fermionic operators that are generated are computed in terms of the fermion propagator functions.

    hep-phhep-thFew Body Syst.(2023)·8 citations
19. 19*

    Computational challenges for multi-loop collider phenomenology

    Fernando Febres Cordero🇺🇸 · Andreas von Manteuffel🇺🇸 · Tobias Neumann🇺🇸

    Precision measurements at the LHC and future colliders require theory predictions with uncertainties at the percent level for many observables. Theory uncertainties due to the perturbative truncation are particularly relevant and must be reduced to fully exploit the physics potential of collider experiments. In recent years the theoretical high energy physics community has made tremendous analytical and numerical advances to address this challenge. In this white paper, we survey state-of-the-art calculations in perturbative quantum field theory for collider phenomenology with a particular focus on the computational requirements at high perturbative orders. We show that these calculations can have specific high-performance-computing (HPC) profiles that should to be taken into account in future HPC resource planning.

    hep-phComput.Softw.Big Sci.(2022)·26 citations
20. 20*

    Low energy SUSY confronted with new measurements of W-boson mass and muon g-2

    Jin Min Yang🇨🇳 · Yang Zhang🇨🇳

    The new CDF II measurement of $W$-boson mass shows a 7$\sigma$ deviation from the Standard Model (SM) prediction, while the recent FNAL measurement of the muon $g-2$ shows a 4.2$\sigma$ deviation (combined with the BNL result) from the SM. Both of them strongly indicate new physics beyond the SM. In this work we study the implication of both measurements on low energy supersymmetry. With an extensive exploration of the parameter space of the minimal supersymmetric standard model (MSSM), we find that in the parameter space allowed by current experimental constraints from colliders and dark matter detections, the MSSM can simultaneously explain both measurements on the edge of $2\sigma$ level, taking theoretical uncertainties into consideration. The favored parameter space, characterized by a compressed spectrum between bino, wino and stau, with the stop being around 1 TeV, may be covered in the near future LHC searches.

    hep-phSci.Bull.(2022)·102 citations
21. 21*

    Impact of the recent measurements of the top-quark and W-boson masses on electroweak precision fits

    J. de Blas🇪🇸 · M. Pierini🇨🇭 · L. Reina🇺🇸 · L. Silvestrini🇮🇹

    We assess the impact of the very recent measurement of the top-quark mass by the CMS Collaboration on the fit of electroweak data in the Standard Model and beyond, with particular emphasis on the prediction for the mass of the W boson. We then compare this prediction with the average of the corresponding experimental measurements including the new measurement by the CDF Collaboration, and discuss its compatibility in the Standard Model, in new physics models with oblique corrections, and in the dimension-six Standard Model Effective Field Theory. Finally, we present the updated global fit to electroweak precision data in these models.

    hep-phPRL(2022)·223 citations
22. 22*

    Sterile neutrino production at small mixing in the early universe

    Gonzalo Alonso-Álvarez🇨🇦 · James M. Cline🇨🇦

    Sterile neutrinos can be produced in the early universe via interactions with their active counterparts. For small active-sterile mixing angles, thermal equilibrium with the standard model plasma is not reached and sterile neutrinos are only produced via flavor oscillations. We study in detail this regime, taking into account matter potentials and decoherence effects caused by elastic scatterings with the plasma. We find that resonant oscillations occurring at temperatures $T\lesssim 10\mathrm{GeV}$ lead to a significant enhancement of the sterile neutrino production rate. Taking this into account, we improve constraints on the active-sterile mixing from Big Bang nucleosynthesis and the cosmic microwave background, excluding mixing angles down to ${\theta }_s\sim 10^{-10}-10^{-16}$ for sterile neutrino masses in the $10\mathrm{MeV}$ to $10\mathrm{GeV}$ range. We observe that if sterile neutrinos predominantly decay into metastable hidden sector particles, this process provides a novel dark matter production mechanism, consistent with the sterile neutrino origin of light neutrino masses via the seesaw mechanism.

    hep-phastro-ph.COPLB(2022)·13 citations
23. 23*

    Probing light mediators at the MUonE experiment

    Giovanni Grilli di Cortona🇮🇹 · Enrico Nardi🇮🇹

    The MUonE experiment, that aims to provide a precise measurement of the hadronic vacuum polarization contribution to the muon $g-2$ via elastic muon-electron scattering, has also the potential to explore the parameter space of light new physics. Exploiting the process ${\mu }^{-}N\to {\mu }^{-}NX$, where $N$ is the target nucleus and X is a new physics light mediator, we demonstrate that MUonE can be sensitive to new regions of parameter space for sub-GeV dark photons. In particular, thanks to its muon beam, MUonE will be able to explore uncharted parameter space regions for the $L_{\mu }-L_{\tau }$ model. Finally, we also find that MUonE can probe the parameter space of axion-like particles for different assumptions of the couplings to electrons, muons and photons.

    hep-phhep-exPRD(2022)·29 citations
24. 24*

    Explaining the GeV antiproton/$\gamma -$ray excesses and W-boson mass anomaly in an inert two Higgs doublet model

    Cheng-Rui Zhu🇨🇳 · Ming-Yang Cui🇨🇳 · Zi-Qing Xia🇨🇳 · Zhao-Huan Yu🇨🇳 · Xiaoyuan Huang🇨🇳 · Qiang Yuan🇨🇳 · Yi-Zhong Fan🇨🇳

    For the newly discovered $W$-boson mass anomaly, one of the simplest dark matter (DM) models that can account for the anomaly without violating other astrophysical/experimental constraints is the inert two Higgs doublet model, in which the DM mass ($m_S$) is found to be within $\sim 54-74$ GeV. In this model, the annihilation of DM via $SS\to b\bar{b}$ and $SS\to W{W}^{\ast }$ would produce antiprotons and gamma rays, and may account for the excesses identified previously in both particles. Motivated by this, we re-analyze the AMS-02 antiproton and Fermi-LAT Galactic center gamma-ray data. For the antiproton analysis, the novel treatment is the inclusion of the charge-sign-dependent three-dimensional solar modulation model as constrained by the time-dependent proton data. We find that the excess of antiprotons is more distinct than previous results based on the force-field solar modulation model. The interpretation of this excess as the annihilation of $SS\to W{W}^{\ast }$ ($SS\to b\bar{b}$) requires a DM mass of $\sim 40-80$ ($40-60$) GeV and a velocity-averaged cross section of $O(10^{-26})\mathrm{c}{\mathrm{m}}^3{\mathrm{s}}^{-1}$. As for the $\gamma$-ray data analysis, besides adopting the widely-used spatial template fitting, we employ an orthogonal approach with a data-driven spectral template analysis. The fitting to the GeV $\gamma$-ray excess yields DM model parameters overlapped with those to fit the antiproton excess via the $W{W}^{\ast }$ channel. The consistency of the DM particle properties required to account for the $W$-boson mass anomaly, the GeV antiproton excess, and the GeV $\gamma$-ray excess suggest a common origin of them.

    ↳ astro-ph.HEhep-phPRL(2022)·91 citations
25. 25*

    Critical Tests of Leading Gamma Ray Burst Theories II

    Shlomo Dado🇮🇱 · Arnon Dar🇮🇱 · A. De Rújula🇪🇸

    It has been observationally established that supernovae (SNe) of Type Ic produce long duration gamma ray bursts (GRBs) and that neutron star mergers generate short hard GRBs. SN-Less GRBs presumably originate in a phase transition of a neutron star in a high mass X-ray binary. How these phenomena actually generate GRBs is debated. The fireball and cannonball models of GRBs and their afterglows have been widely confronted with the huge observational data, with their defenders claiming success. The claims, however, may reflect multiple choices and the use of many adjustable parameters, rather than the validity of the models. Only a confrontation of key falsifiable predictions of the models with solid observational data can test their validity. Such critical tests are reviewed in this report.

    ↳ astro-ph.HEhep-phSpecial issue on GRBs, MDPI journal "Univ…·6 citations
26. 26*

    Nonequilibrium effects and transverse spherocity in ultra-relativistic proton-nucleus collisions

    Lucia Oliva🇮🇹 · Wenkai Fan🇺🇸 · Pierre Moreau🇺🇸 · Steffen A. Bass🇺🇸 · Elena Bratkovskaya🇩🇪

    We investigate the effects of nonequilibrium dynamics in small colliding systems by comparing a nonequilibrium transport approach, the Parton-Hadron-String-Dynamics (PHSD), with a (2+1)D viscous hydrodynamic model, VISHNew. Focusing on p+Pb collisions at LHC energy, we extract the initial conditions for the hydrodynamic model from PHSD, in order to reduce the impact of the early out-of-equilibrium dynamics and focus on the traces of nonequilibiurm in the ensuing medium evolution. We find that in the transport approach quantities like energy density and bulk viscous pressure are highly inhomogeneous on the transverse plane during the whole evolution, whereas the hydrodynamic simulations dissolve more efficiently the initial spatial irregularities, still keeping a high degree of inhomogeneity due to the smaller size and lifetime of the medium produced in p+Pb collisions with respect to heavy-ion reactions. As a first step that will help to identify the impact of these nonequilibrium effects on final observables in proton-nucleus collisions, we perform an analysis of the transverse spherocity, an event-shape observable able to distinguish between jetty and isotropic configurations of transverse momenta. We found that the spherocity distribution in PHSD is slightly shifted towards the isotropic limit with respect to the hydrodynamic result. Even though this dissimilarity is partially due to the difference in the final charged particle production, it mainly comes from the different description within the two frameworks of the medium produced in small colliding systems. This finding supports the idea that multi-differential measurements, such as those based on event categorization according to multiplicity and spherocity, are useful to study final-state observables in ultrarelativistic proton-nucleus collisions.

    ↳ nucl-thhep-phPRC(2022)·8 citations
27. 27*

    Investigation of CMB constraints for dark matter-helium scattering

    Kimberly K. Boddy🇺🇸 · Gordan Krnjaic🇺🇸 · Stacie Moltner🇺🇸

    We study dark matter-helium scattering in the early Universe and its impact on constraints from cosmic microwave background (CMB) anisotropy measurements. We describe possible theoretical frameworks for dark matter-nucleon interactions via a scalar, pseudoscalar, or vector mediator; such interactions give rise to hydrogen and helium scattering, with cross sections that have a power-law dependence on relative velocity. Within these frameworks, we consider three scenarios: dark matter coupling to only neutrons, to only protons, and to neutrons and protons with equal strength. For these various cases, we use \textit{Planck} 2018 temperature, polarization, and lensing anisotropy data to place constraints on dark matter scattering with hydrogen and/or helium for dark matter masses between 10 keV and 1 TeV. For any model that permits both helium and hydrogen scattering with a non-negative power-law velocity dependence, we find that helium scattering dominates the constraint for dark matter masses well above the proton mass. Furthermore, we place the first CMB constraints on dark matter that scatters dominantly/exclusively with helium in the early Universe.

    ↳ astro-ph.COhep-phPRD(2022)·22 citations
28. 28*

    Gravitational Waves from Domain Walls in Pulsar Timing Array Datasets

    Ricardo Z. Ferreira🇪🇸 · Alessio Notari🇪🇸 · Oriol Pujolas🇪🇸 · Fabrizio Rompineve🇨🇭

    We present a model-independent search for the gravitational wave background from cosmic domain walls (DWs) in the NANOGrav 12.5 years dataset and International PTA Data Release 2. DWs that annihilate at temperatures $\sim 20-50\text{MeV}$ with tensions $\sim (40-100\text{TeV}{)}^3$ provide as good a fit to both datasets as the astrophysical background from supermassive black hole mergers. DWs may decay into the Standard Model (SM) or a dark sector. In the latter case we predict an abundance $\Delta N_{\text{eff}}$ of dark radiation well within the reach of upcoming CMB surveys. Complementary signatures at colliders and laboratories can arise if couplings to the SM are present. As an example, we discuss heavy axion scenarios, where DW annihilation may interestingly be induced by QCD confinement.

    ↳ astro-ph.COastro-ph.HEgr-qchep-phJCAP(2023)·141 citations
29. 29*

    Dark Matter constraints from Planck observations of the Galactic polarized synchrotron emission

    Silvia Manconi🇩🇪 · Alessandro Cuoco🇮🇹 · Julien Lesgourgues🇩🇪

    Dark Matter (DM) annihilation in our Galaxy may produce a linearly polarized synchrotron signal. We use, for the first time, synchrotron polarization to constrain the DM annihilation cross section by comparing theoretical predictions with the latest polarization maps obtained by the Planck satellite collaboration. We find that synchrotron polarization is typically more constraining than synchrotron intensity by about one order of magnitude, independently of uncertainties in the modeling of electron and positron propagation, or of the Galactic magnetic field. Our bounds compete with Cosmic Microwave Background limits in the case of leptophilic DM.

    ↳ astro-ph.HEastro-ph.COhep-phPRL(2022)·8 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.